Cellulosic and lignocellulosic feedstocks and wastes, such as agricultural residues, wood, forestry wastes, sludge from paper manufacture, and municipal and industrial solid wastes, provide a potentially large renewable biomass feedstock for the production of chemicals, plastics, fuels and feeds. Cellulosic and lignocellulosic feedstocks and wastes, composed of carbohydrate polymers comprising cellulose, hemicellulose, glucans and lignin are generally treated by a variety of chemical, mechanical and enzymatic means to release primarily hexose and pentose sugars, which can then be fermented to useful products. These treatments vary in complexity and efficiency. Further, there are many ongoing efforts to identify new commercially robust processes and to optimize known processes to generate useful fermentative products from cellulosic and lignocellulosic feedstocks.
In order to be an economically competitive process, a commercial process for the production of fermentable sugars from a renewable resource biomass requires the hydrolysis of carbohydrates in lignocellulosic biomass to provide high yields of sugars at high concentrations, using low amounts of chemicals, to produce a source of fermentable sugars with low toxicity toward fermentative organisms that convert sugars to value-added chemicals and fuels.
In order to carry out these processes, a variety of apparatuses have been employed for different types of biomass, as well as for different treatments, including small-scale process development and some large-scale production equipment. Some types of apparatuses that have been used include a batch-stirred reactor (Gusakov and Sinitsyn, (1985) Enz. Microb. Technol. 7:346-352), a continuous flow stirred reactor (U.S. Pat. No. 4,257,818), an attrition reactor (Ryu and Lee (1983) Biotechnol. Bioeng. 25:53-65), an extrusion reactor (U.S. Pat. No. 6,176,176), the NREL shrinking bed reactor (Lee et al. (2001) Appl. Biochem. Biotech. 91-93: 331-340), and a reactor with intensive stirring induced by an electromagnetic field (Gusakov et al. (1996) Appl. Biochem. Biotechnol., 56:141-153).
In particular, a reactor that is capable of providing means for efficient biomass pretreatment and/or saccharification at a high dry weight of biomass in a mixture is needed.
There remains a need for a simple, yet effective apparatus for use in biomass treatment processes, which may be used in a small-scale format for testing process conditions, with mechanisms for sampling that mimics operation in a large commercial scale. Moreover, there is an unmet need for commercially robust processes and equipment to carry out such processes, including saccharification at a high dry weight of biomass in a biomass mixture.